Engineered for enthusiasts seeking maximum protection and performance. Precision-formulated with cutting-edge technology and a longstanding devotion to making the world's best motor oil. The result: engine protection that blows the doors off the highest industry standards.

• 50% more cleaning power vs. AMSOIL OE Motor Oil• Ideal for turbos & direct injection• Guaranteed protection for up to 25,000 miles or 1 year

Protects Against Engine Wear
AMSOIL Signature Series Synthetic Motor Oil develops a strong fluid film that keeps metal surfaces separated while its robust anti-wear additives further reduce wear in metal-to-metal contact regions for maximum engine life. The Sequence IVA Engine Test, which must be passed to meet the industry-standard API SN specification, simulates extended periods of stop-and-go driving. For 100 hours, the test engine cycles between 50 minutes of idling and 10 minutes of elevated rpm – conditions that encourage engine wear. The camshaft is then measured for wear in 84 locations and an average score is determined. We used Signature Series 0W-20, the lightest viscosity in the line, to further increase the severity of the test. AMSOIL Signature Series Synthetic Motor Oil provided 75 percent more engine protection against horsepower loss and wear1 than required by the industry standard, extending the life of vital components like pistons and cams.

After rigorous third-party testing, the cam lobes show little-to-no wear.

SEQUENCE IVA ENGINE TEST
Lower number = less wear

1Based on independent testing of AMSOIL Signatur e Series 0W-20, in ASTM D6891 as required by the API SN specification.

Protects Pistons from Low-Speed Pre-Ignition
We armed Signature Series with an advanced detergent
system that protects against harmful deposits and low-speed
pre-ignition (LSPI). Most new engines feature gasoline direct
injection (GDI), often combined with a turbocharger to boost
power and improve fuel economy. These new technologies,
when combined with a poorly formulated motor oil, promote
LSPI and threaten engine operation. LSPI is the spontaneous
ignition of the fuel/air mixture prior to spark-triggered ignition.
It occurs in today's advanced engines and is much more
destructive than typical pre-ignition. A properly formulated
motor oil is critical for protecting your engine.

Original equipment manufacturers (OEMs) like GM* have
addressed the issue by designing tests to determine a motor
oil’s ability to prevent LSPI. Signature Series Synthetic Motor Oil
achieved 100 percent protection against LSPI1 in the engine test required by the GM dexos1 Gen 2 specification - zero occurrences were recorded throughout five consecutive tests.

Protects Turbochargers
Our unique synthetic formulation is inherently stable to resist oxidation and neutralize acids. Signature Series Motor Oil
provides outstanding protection against deposits common
to high-temperature engine environments. The tremendous
heat and stress turbos create can cause some oils to break
down and form harmful bearing deposits through a process
known as turbo coking. Over time, turbos can suffer reduced
performance or fail altogether.

We challenged Signature Series to the GM Turbo Coking
Test, which consists of 2000 cycles of extreme heat
soaks. An oil must limit the temperature change within the
turbocharger to 13 percent or less to pass the test. Signature
Series limited the temperature increase to only 3.6 percent,
protecting the turbocharger 72 percent better than
required2 by the GM dexos1® Gen 2 specification.

Extends Drains: Protection Guaranteed
AMSOIL Signature Series Synthetic Motor Oil provides reserve protection, allowing you to go longer between oil changes if you choose – up to 25,000 miles, 700 hours of operation or one year, whichever comes first*. Our unique synthetic formulation and long-drain additive system are inherently stable to resist oxidation and neutralize acids over longer periods. Signature Series is designed to deliver outstanding engine protection, cleanliness and performance over extended drain intervals – guaranteed. It provides peace of mind so you can fit oil changes into your schedule.

1 Based on independent testing of AMSOIL Signature Series 5w-30 motor oil, in the LSPI engine test as required for the GM dexos 1® Gen 2 specification.2 Based on independent testing of AMSOIL Signature Series 5W-30 in the GM turbo coking test.3 vs. AMSOIL OE Motor Oil4 Based on independent testing of AMSOIL Signature Series 5W-30 in the ASTM D6593 engine test for oil screen plugging as required by the API SN specification.* All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are developed by AMSOIL for use in the applications shown.

Preserves Horsepower
The extreme durability of Signature Series Motor Oil ensures your engine runs stronger, for longer. We installed Signature Series 5W-30 Synthetic Motor Oil in a Ford* F-150 with a new 3.5L Ecoboost engine to test its ability to protect turbocharged direct-injection (TDGI) engines from torque and horsepower loss during extended drain intervals up to 25,000 miles. Power sweeps were done at the beginning and end of the test to evaluate horsepower and torque retention. As the graph shows, Signature Series helped maintain engine performance throughout the 100,000 mile test.

Limits Oil Consumption
Signature Series has a uniform molecular structure that limits evaporation and keeps it where it's needed most – protecting your engine. Volatility (burn-off) occurs when oil gets hot, causing lighter molecules to burn off or evaporate. This leads to oil thickening, additive imbalance, higher emissions and oil consumption. The NOACK Volatility test is the industry standard for evaluating motor oil high temperature evaporation. It measures the percentage of burn-off after a motor oil is placed under constant airflow at 482ºF for 1 hour. A lower number indicates a better resistance to evaporation. Signature Series falls far below the API limit for volatility, reducing the need for frequent oil top-offs and limiting vehicle emissions.

Maintains Protective Viscosity
We formulated Signature Series with superior thermal durability that resists breakdown better than conventional and synthetic motor oils. The Sequence IIIH Test uses the Chrysler 3.6L Pentastar engine to evaluate a motor oil's ability to resist the damaging effects of heat. The test is conducted with oil temperatures of 304ºF, 100ºF hotter than normal operation, to accelerate oil thickening and deposits. Despite the extreme conditions, Signature Series kept pistons clean and held thickening to only 6 percent, a minimal amount compared to the proposed specification limit of 150 percent.1 This stay-in-grade performance helps maintain maximum power and fuel economy while also ensuring advanced technologies like variable valve timing (VVT) operate as designed throughout the entire drain interval.

1 Based on proposed ILSAC GF-5 Plus specification.* All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are developed by AMSOIL for use in the applications shown.

More about AMSOIL Reviews

AMSOIL requests reviews via email from verified customers that have purchased products through
the AMSOIL corporate website or by telephone. This process ensures valuable, authentic reviews.
We also encourage you to submit a testimonial detailing your experience with AMSOIL products.

All trademarked names and images are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use. All products advertised here are AMSOIL-engineered for use in the applications shown.